Why many of the coronary perforations during PCI are benign ?

Coronary artery perforation is a dreaded complication of PCI. Perforations are the Interventional cardiologists ultimate worry as they need to manipulate their hardware for long periods in many complex lesions. Especially it is a real threat in chronic total occlusions.

Still , an important fact is , many of the coronary perforations are not life threatening ?

How is this possible ? (Type 1 Ellis has zero mortality Read below)

As the guide wire injures and perforates the cor0nary vessel, it results in small puffs of dye extravasating into peri coronary space .

The coronary artery , which is located within the atrioventricular groove (LAD), or AV groove (LCX, RCA) have two distinct anatomical relationship with reference to epicardium and pericardial space.

50 % 0f circumference of the coronary artery is hugged by the myocardium another 50% or so is related directly to the pericardial aspect.

Guide wires hitting on the myocardial aspects face a stiff resistance than the pericardial aspect. So , generally the risk of perforating pericardial aspect is more than myocardial aspect

Even if , the coronary artery is punctured on myocardial aspect , no great danger occur as there is no potential space for the blood to drain and further, the elastic nature of myocardial muscle plane effectively seals the leak. At the most , mild myocardial staining is noted .

While , perforations into the pericardial space , often threaten with a tamponade. The fact that pericardial space has negative pressure and the mean coronary arterial pressure around 40mmhg , it is , all the more likely blood is sucked into the pericardial space. Of course , very minute perforations even into the pericardial space , could be self limited and benign.

What is unrecognised coronary perforation?

Many times , the guidewire goes in a false track in the tissue plane.This is nothing, but perforation without hemodynamic implication. Most often , these are the instances of guide wire entering the epicardium.They mimic , false lumen entry , dissections, etc. There are occasion , where false lumen of the coronary artery were stented.

Simple guide wire induced perforations are less trouble some unless we have crossed it with balloon without realising the fact the wire has entered the pericardial space. So, caution is required and always watch for guide wire tip movement which is often funny looking wihtin false lumens or very freely moving within pericardial space. Anticipate the complication especially so when you do CTOs and venous graft PCI. Keep one cath lab tamponade crash bin in ready mode before embarking upon a complex PCI

Neutralise the heparin action with protamine is the first step

Most are self limited, no intervention is required but requires close observation for next 24 hours.

Temporary balloon occlusion may be suffice in many cases

Tamponade requires immediate tapping. Small collection without fall in BP can be observed.

keep doing the echocardiogram liberally to assess the leak and watch for any new collection.

PTFE covered stents if prolonged leak.

Emergency surgery may required in few.

2018 update

This is nearly 10 years old article. Now, we have gained much experience and hardware utilisation have rapidly expanded. While expertise has minimised this complication , more PCIs in complex lesion subset tend to keep the incidence static , if not higher.(Its around .5% )

Perforations which are active and flowing should be immediately occluded with a balloon either at the site of leak or just proximal to it. Doing a proximal occlusion is easier in emergency , as often times its technically difficult to reach the site of leak especially in CTOs where the leaky site is not defined clearly or forward looking (Local balloon inflation across the leaky site is not feasible )

How long to occlude , Intermittent /complete, proximal ? or at the site of perforation ? These queries are answered in Ref 4